Valar's Nuclear Safety Design Agreement for Ward 250 (document 100403 rev 02, October 2025, marked 'Draft' and 'issued for Public Release'; the company says DOE approved it) lists key design parameters: 100 kWth continuous as the license limit, up to 250 kWth for limited tests; TRISO-coated UCO fuel qualified on the AGR program basis; helium coolant at 3.0 MPa; 250 C inlet and 650 C nominal core outlet; a 1.8 m by 1.5 m core of 76 fuel elements holding about 250 kg of heavy metal; 4.95% U-235 enrichment; graphite reflector. It sets a 12-month operating period and an 18-month lifecycle ending in decommissioning and return of the site to unrestricted use, with DOE authorization only and no planned NRC licensing. At a July 2025 Emery County town hall the name was explained as a reference to the nation's 250th birthday on July 4, 2026 (orig-045); the 250 kWth test ceiling is a separate figure.

• Ward250 Nuclear Safety Design Agreement (Document 100403, Rev. 02) (Valar Atomics, 2025-10) primary filing “a ≤250 kWth High Temperature Gas-cooled Reactor (HTGR) research facility”
• Ward250 Nuclear Safety Design Agreement (Valar Atomics, 2025-10-13) primary company “The Department of Energy has approved the Nuclear Safety Design Agreement (NSDA)”